1. Field of the Invention
The present invention relates to a traffic cone counterweight structure designed primarily for saving the production cost of traffic cones. The traffic cone is made by first fabricating its base and then forming the cone body by injection molding. As such, the base of traffic cone can be made of materials with less fluidity or recycled material, or even scrap material from waste tires by stamping and extruding, thereby reducing the material cost of the base without compromising the original warning effect of the traffic cone and its counterweight requirement. Also, the production of such traffic cones can use existing molds for making integrally-formed traffic cones directly without the need to fabricate a separate mold, hence offering excellent utilization value and economic benefit for the industry.
2. Description of the Related Art
Conventional traffic cones are made of plastic or rubber material in one piece by injection molding. A traffic cone generally comprises a cone body and a base at the bottom, where the base enhances its upright stability, while the cone body provides the warning effect. With such a structural design, the cone body uses a reflective material, which reflects the light from automobile headlights at nighttime to enhance the warning effect. For the upright stability of the traffic cone, its base incorporates different counterweights to address the varying needs on different occasions and the regulatory requirements for road signs in different areas.
Such an integrally-formed traffic cone is made of a single material and confined in terms of shape. Because its cone body is thinner and bigger in size, only materials with better fluidity can be used to make sure the material will fill the mold during a limited time in the process of injection molding. Also to achieve a better reflection effect, the production of traffic cone must use better quality material, blended with phosphors for injection molding, without the option of using lower-grade or recycled material. As a result, the production cost of traffic cones stay high. On the other hand, if cost is a prime consideration and material with poor fluidity is used for injection molding, the cone body tends to break or results in defects during molding, which leads instead to material waste. In addition, traffic cones have a counterweight requirement, which poses a considerable technical challenge in the production process. Thus the traffic cones disclosed in U.S. Pat. No. 6,929,419 and U.S. Pat. No. 7,056,055 are designed to have the cone body and base fabricated separately, in which the cone body is first made by injection molding and then placed in the base mold. When the base is formed, it wraps around the cone body. To make sure the cone body and the base are securely coupled to each other, the cone body is provided with an annular enclosure at its bottom, on which through-holes or upright bars are disposed. By placing the annular enclosure at the bottom of cone body in the base mold, the material used for the formation of base will flow through the through-holes and wraps around the annular enclosure to lock with the cone body through the upright bars and through-holes, thereby enhancing their coupling strength. Also, to address varying counterweight requirements, molds of different specifications can be used to fabricate bases with varying counterweights and thicknesses to meet the specific requirements for traffic cones.
The design of fabricating the cone body and base in separate processes as disclosed in the aforementioned patents solves the base counterweight problem. But in those patents, thermofusible material with better fluidity must be used for the fabrication of base in order for the material to flow through the through-holes and upright bars disposed on the annular enclosure of cone body and wrap around the annular enclosure snugly. Generally materials with better fluidity cost more. As such, the aforementioned patents effectively address the counterweight issue of traffic cone, but tend to jack up its production cost, thus lacking utilization value and economic benefit, and leaving room for improvement.
Also in the aforementioned patents, the cone body of a traffic cone is first formed by injection molding and then placed in the base mold to produce a base that wraps around the cone body. As such, existing molds for traffic cones are of no use, while separate molds for the cone body and the base have to be fabricated. In addition, the thickness of the base must vary to meet different counterweight specifications, while the height of upright bars on the cone body must match the height of the base. Under the circumstances, traffic cone manufacturers must make separate molds for the cone body and base with different counterweight specifications, which greatly increases the mold cost. In fact, the increase in cost far surpasses the saving achieved by using low-priced material, hence lacking economic benefit. Moreover, when making traffic cones with different counterweight specification, the mold needs to be changed and calibrated, which is time consuming, thereby adversely affecting the production efficiency. Thus the design for traffic cones mentioned above is hardly ideal.